(a) Technical Field
The present disclosure of invention relates to a display device capable of displaying 3D images and to a driving method thereof, and in more detail, it relates to a 3D image display device including a shutter member and a driving method thereof.
(b) Description of Related Technology
A flat or otherwise thin display device such as a liquid crystal display (LCD) and an organic light emitting diodes display (OLEDD) generally includes a display panel and a driving device for electrically driving the display device.
The display panel includes a plurality of signal lines and a plurality of pixels connected thereto and arranged substantially in a matrix form. The signal lines include a plurality of gate lines configured for transferring gate signals, a plurality of data lines configured for transferring data voltages, and the like.
Each pixel may include at least one switching element connected with a corresponding gate line and with a corresponding data line, and at least one pixel electrode operatively coupled to the switching element. The pixel may additionally include an opposed electrode that electrically interacts with the pixel electrode, where the opposed electrode may be configured to receive a common voltage. The switching element may include at least one thin film transistor (TFT), and may selectively transfer to its pixel electrode a data voltage transferred by the data line which is turned on or off according to a gate signal transferred by the gate line, to the TFT. Each pixel may display an image portion having a corresponding luminance according to the data voltage applied to the pixel electrode.
The electrical driving device includes a gate lines driver configured for generating gate signals and a data lines driver configured for generating data voltages. It additionally includes a gamma reference voltages generator configured for supplying one or more gamma reference voltages to the data lines driver and it includes a signal controller configured for controlling the gate lines driver, the data driver, and the gamma reference voltages generator, and the like. The drivers may be installed on the display panel in at least one IC chip form, attached to the display panel in a TCP form, or monolithically integrated on the display panel.
The electrical driving device is configured to convert a received digital input image signal, which signal includes grayscale information into a corresponding analog image signal by using one or more reference grayscale voltages and it supplies the produced analog image signal to each pixel, thereby displaying the image. The reference grayscale voltage(s) may vary according to provided gamma data where the latter provides information on a desired gray level and on a slope of luminance of the image created as the voltage selected for the data line driving data voltage changes in response to gray voltages represented by the input image signal.
The reference grayscale voltages include a set of positive gray voltages and a set of negative gray voltages where the positive versus negative polarity is relative to a supplied or predetermined common voltage. Fine resolution grayscale voltages may be generated by interpolating as between the positive and negative gamma reference voltages where the latter are smaller in number than the fine resolution gray voltages.
A gamma reference voltages generator provided within the driving device may be configured to receive a power supply voltage or a reference voltage, and to divide the received voltage to generate from it a plurality of positive and negative gamma reference voltages.
The data driver receives the positive and negative gamma reference voltages from the gamma reference voltages generator and divides the received gamma reference voltages to generate fine resolution gray voltages for all grays that can be commanded by the received digital input image signal. The data driver selects a gray voltage corresponding to the input image signal among a plurality of gray voltages to apply the selected gray voltage as a data voltage to the data line.
A voltage gap may be provided between the common voltage and the immediately next adjacent positive and negative gamma reference voltages. This gap is referred to as a black gap. If a voltage within the black gap is applied to the display panel, a black screen is displayed.
Meanwhile, as display device technology has developed, 3D image displaying devices have come into popularity and various methods for displaying 3D images have been studied.
Generally, within the 3D image displaying technologies, one approach for creating a 3D effect relies on binocular parallax where different images are respectively displayed to the left and right eyes of the user. The binocular parallax approach is highly useful for allowing a person to perceive a stereoscopic effect at a close range for example when operating a small screen portable device (e.g., a smartphone). That is, different 2D images are respectively projected for receipt by a right eye and by a left eye, and if the image seen by the left eye (hereinafter referred to as a “left-eye image”) and the image seen by the right eye (hereinafter referred to as a “right-eye image”) are transmitted to the brain, the left-eye image and the right-eye image may be combined by the brain such that a 3D image allowing for depth perception is recognized.
The 3D image display devices using the binocular disparity in 3D image displays are typically categorized as stereoscopic schemes using glasses such as a shutter glasses scheme and a polarized glasses scheme, and autostereoscopic schemes in which a lenticular lens or a parallax barrier is disposed on the display device without the need for the user to wear special glasses.
In the 3D image display panel of the shutter glasses scheme, the left-eye image and the right-eye image are separated and continuously output, and the left-eye shutter and the right-eye shutter of the shutter glasses are selectively shut off by control of a shutter controller such that the 3D image is displayed.
Also in the shutter glasses scheme, as one example of a driving method when displaying the 3D image, there is an insertion of an image frame all of a predetermined gray (e.g., a black gray) between a first nonblackened frame (referred to as “a left eye image display frame”) displaying a left eye image and a second nonblackened frame (referred to as “a right eye image display frame”) displaying a right eye image. In case of a method inserting the image frame of the black gray between the left eye image display frame and the right eye image display frame, crosstalk in which the left eye image and the right eye image appear to be overlapped may be reduced, however the luminance of the 3D image may be largely decreased by an influence on the human visual system of the insertion of the image frames of the black gray.
Additionally, in the shutter glasses scheme, as another example of a driving method displaying the 3D image, there is a method of maintaining the left eye image or the right eye image charged in the previous frame without application of the image creating data voltages or of repeating an applying of the data voltages for the same left eye image or right eye image as the previous frame instead of using the image frame of the black gray between the left eye image display frame and the right eye image display frame. In the case of this method, the image frame of the black gray is not inserted such that the luminance performance is improved, however crosstalk between the left eye image and the right eye image may be disadvantageously increased.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.